Smoking article filters

ABSTRACT

The present invention relates to improvements in filters for use in smoking articles such as cigarettes, cigars and cigarillos. The improvements, particularly but not exclusively, relate to filter capabilities and to the manufacture of such filters. In one example, a filter for a smoking article comprises a first fibrous filter material having an average fibre denier in the range 7 to 9 and a second fibrous filter material having an average fibre denier of below 7. The application also describes a filter for a smoking article comprising various other filter arrangements including absorbent and/or adsorbent materials.

TECHNICAL FIELD

The present invention relates to improvements in filters for use insmoking articles. Particularly but not exclusively the improvementsrelate to filter capabilities and to the manufacture of such filters.

BACKGROUND

A known filtering material used in cigarette filters is a continuous towof filamentary cellulose acetate plasticised with triacetin. Thecellulose acetate is gathered together to form a rod which is cut toform individual filter segments. The filter for a smoking article may bemade of one segment of filter rod, or may be made from multiplesegments, with or without a cavity or spaces between them.

SUMMARY

According to embodiments of the invention, there is provided a filterfor a smoking article comprising a first fibrous filter material havingan average fibre denier in the range 7 to 9 and a second fibrous filtermaterial having an average fibre denier of below 7, wherein the secondfibrous filter material is dispersed within the first fibrous filtermaterial, and wherein the first and second fibrous filter materialscomprise discrete short length fibres which are randomly oriented in thefilter.

The randomly oriented short length fibres can be held together in thefilter without the use of a plasticiser.

The first and/or second fibrous filter materials can comprise fibreshaving an average length of from about 5 mm to 20 mm when extended.

The second fibrous filter material can have an average fibre denier inthe range from 1 to 6.

The second fibrous filter material can comprise a plurality of nanofibres.

The nanofibres can carry an additive for the selective reduction of atleast one constituent of smoke drawn through the filer in use.

According to embodiments of the invention, there is further provided afilter for a smoking article comprising a sheet material dispersedwithin randomly oriented short length fibres.

The sheet material can comprise shredded sheet material selected from atleast one of polyvinyl alcohol (PVOH), polylactic acid (PLA),poly(ε-caprolactone)(PCL), poly(1-4 butanediol succinate) (PBS),poly(butylene adipate-co-terephthalate)(PBAT), starch based materials,paper, aliphatic polyester materials and polysaccharide polymers.

According to embodiments of the invention, there is further provided afilter for a smoking article comprising randomly oriented short lengthfibres formed from a first material and randomly oriented short lengthfibres formed from a second material.

The first material can comprise cellulose acetate.

The second material can comprise a non-crimped material.

The second material can comprise at least one material selected frompolyvinyl alcohol (PVOH), polylactic acid (PLA),poly(ε-caprolactone)(PCL), poly(1-4 butanediol succinate)(PBS),poly(butylene adipate-co-terephthalate)(PBAT), starch based materials,paper, aliphatic polyester materials and polysaccharide polymers.

The filter can be formed into a shape other than a cylinder or into acylinder having a circumference smaller than 16 mm or a circumferencegreater than 25 mm.

The filter can further comprise a flavour release component.

According to embodiments of the invention, there is further provided asmoking article comprising a filter as set out above.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic illustration of a smoking article having a filterwith at least one segment having from 12 mg of adsorbent material permillimetre of length and 4 mg of absorbent material per millimetre oflength, for a regular format filter;

FIG. 2 is a schematic illustration of a filter making apparatus for usein manufacturing filters;

FIG. 3 is a graph illustrating the carbon weight and tow weight infilters based on desired ranges for filter pressure drop and hardness;

FIG. 4 provides three graphs respectively illustrating the influence ofcarbon weight, tow weight and machinery operating speed on pressure dropfor filters;

FIG. 5 provides three graphs respectively illustrating the influence ofcarbon weight, tow weight and machinery operating speed on hardness forfilters;

FIG. 6 is a schematic illustration of a smoking article having a filterwith a first fibrous filter material having an average fibre denier inthe range 7 to 9 and a second fibrous filter material, dispersed withinthe first fibrous filter material, having an average fibre denier ofbelow 7;

FIG. 7 is a schematic illustration of a smoking article having a filterwith at least one segment including a nanofibre carrying an additive forenabling or enhancing the reduction of at least one component of mainstream smoke;

FIG. 8 is a schematic illustration of a smoking article having a filterwith at least one segment comprising randomly oriented discrete shortlength fibres having a thread extending therethrough;

FIG. 9 is a schematic illustration of a smoking article having a filterwith at least one segment comprising randomly oriented discrete shortlength fibres having a capsule disposed therein;

FIG. 10 is a schematic illustration of a smoking article having a filterwith at least one segment comprising randomly oriented discrete shortlength fibres having microcapsules disposed therein;

FIG. 11 is a schematic illustration of a smoking article having a filterwith at least one segment comprising randomly oriented discrete shortlength fibres having shredded sheet material disposed therein;

FIG. 12 is a schematic illustration of a smoking article having a filterwith at least one segment comprising randomly oriented discrete shortlength fibres having degradable fibres disposed therein;

FIG. 13a is a schematic illustration of a filter rod comprising regionsof higher average density and regions of lower average density;

FIG. 13b is a schematic illustration of a section of a filter formingband for producing filter segments having regions of higher averagedensity and regions of lower average density;

FIG. 14 is a schematic illustration of a smoking article having a filtercomprising an elliptical cross-section; and

FIG. 15 is a schematic illustration of a smoking article having a filtercomprising a square cross-section.

DETAILED DESCRIPTION

As used herein, the term “smoking article” includes smokeable productssuch as cigarettes, cigars and cigarillos whether based on tobacco,tobacco derivatives, expanded tobacco, reconstituted tobacco or tobaccosubstitutes and also heat-not-burn products. Such smoking articles maybe provided with a filter for the gaseous flow drawn by the smoker.

Smoking articles such as cigarettes and their formats are often namedaccording to the cigarette length: “regular” (typically in the range68-75 mm, e.g. from about 68 mm to about 72 mm), “short” or “mini” (68mm or less), “king-size” (typically in the range 75-91 mm, e.g. fromabout 79 mm to about 88 mm), “long” or “super-king” (typically in therange 91-105 mm, e.g. from about 94 mm to about 101 mm) and “ultra-long”(typically in the range from about 110 mm to about 121 mm).

They are also named according to the cigarette circumference: “regular”(about 23-25 mm), “wide” (greater than 25 mm), “slim” (about 22-23 mm),“demi-slim” (about 19-22 mm), “super-slim” (about 16-19 mm), and“micro-slim” (less than about 16 mm). Accordingly, a cigarette in aking-size, super-slim format will, for example, have a length of about83 mm and a circumference of about 17 mm. Cigarettes in the regular,king-size format are preferred by many customers, namely with acircumference of from 23 to 25 mm and an overall length of from 75 to 91mm.

Each format may be produced with filters of different lengths, smallerfilters being generally used in formats of smaller lengths andcircumferences. Typically the filter length will be from 15 mm,associated with short, regular formats, to 30 mm, associated withultra-long super-slim formats. The tipping paper will have a greaterlength than the filter, for example from 3 to 10 mm longer.

FIG. 1 is a schematic illustration of a smoking article 1 having afilter. The smoking article 1 is in the regular, king size format,namely having a length in the range 75-91 mm and a circumference in therange 23 to 25 mm. The smoking article 1 includes a tobacco rod 2wrapped in a wrapping material 3, in this case cigarette paper,connected longitudinally to a filter 4 by tipping material 5 overlayingthe filter 4 and partially overlaying the wrapping material 3. Thefilter 4 comprises a first segment 6 at the mouth-end of the filter 4comprising crimped cellulose acetate tow 7 wrapped in a first plug wrap8, and a second segment 9 at the tobacco rod end of the filter 4comprising absorbent material 10 having an adsorbent material 11dispersed therein and wrapped in a second plug wrap 12.

The first segment 6 is a cellulose acetate segment formed usingcontinuous cellulose acetate fibres and a plasticiser.

The absorbent material 10 of the second segment 9 comprises randomlyoriented discrete short length cellulose acetate fibres and theadsorbent material 11 comprises activated carbon particles. The randomlyoriented discrete short length cellulose acetate fibres of the secondsegment 9 are non-plasticised fibres. The randomly oriented discreteshort length cellulose acetate fibres of the second segment 9 comprise 8denier, 10 mm fibre lengths. However, other denier fibres or fibrelengths can be used. For instance, fibre deniers in the range 5 to 9 or7 to 9 can be used. In terms of fibre length, when used herein, the term‘short length’ means fibre lengths of fibres in the form used in afilter segment (i.e. crimped or uncrimped as appropriate) which areshorter than the length of the filter segment. Average fibre lengths(when the fibres are extended) in the range from 5 mm to 25 mm, or from6 mm to 20 mm, 7 mm to 20 mm or 7 mm to 15 mm can be used. The activatedcarbon particles are in the present example coconut carbon provided in a30/70 mesh size, although other carbons and/or sizes can be used. Forinstance, particles with diameters in the range of approximately 0.1 to1.0 mm, or approximately 0.2 to 0.9 mm, 0.2 to 0.8 mm, 0.2 to 0.7 mm,0.2 to 0.6 mm, 0.3 to 0.9 mm, 0.3 to 0.8 mm, 0.3 to 0.7 mm or 0.3 to 0.6mm can be used.

The second segment 9 has 12 mg of adsorbent material per millimetre oflength and 4 mg of absorbent material per millimetre of length. However,in alternative examples, the amount of adsorbent can be anywhere in therange from 6 mg to 16 mg per mm length on average, or from 7 mg to 16mg, 8 mg to 16 mg, 9 mg to 16 mg, 10 mg to 16 mg, 11 mg to 16 mg, 12 mgto 16 mg, or 13 mg to 16 mg per mm length and the amount of absorbentcan be from 1.5 mg to 8 mg per mm length on average, or from 1.5 mg to 7mg, 1.5 mg to 6 mg, 1.5 mg to 5 mg, or 1.5 mg to 4 mg, all of theseranges being for a regular format filter, i.e. having a circumference ofabout 23 to 25 mm. It has been found that these parameters enable thefilter to exhibit desirable pressure drop and hardness levels forconsumer acceptable smoking articles, while increasing the level ofadsorbent or other granular additive in the filter over known filters.

The filter material of the second segment 9, for instance, exhibitsdesirable pressure drop in the range 500 to 700 mmWg for an experimentalsample having a 144 mm filter length (3.47 to 4.86 mmWg/mm) anddesirable hardness of between 85% to 95% according to the Filtronafilter hardness measure (defined as the compressed diameter of thefilter rod as a percentage of the initial rod diameter, the compressionof the rod being caused by a known weight applied through a circularfoot for a specific period of time). Alternative weights of adsorbentmaterial and absorbent material per mm of filter length would be usedfor filters in formats other than regular, for instance having slimmeror wider average diameters, as would be appreciated by those skilled inthe art.

An increase in the pressure drop and/or hardness percentage resultingfrom an increase in the amount of adsorbent per mm in a filter can beoffset by a decrease in the amount of absorbent per mm. Also, anincrease in the pressure drop and/or hardness percentage resulting froman increase in the amount of absorbent per mm in a filter can be offsetby a decrease in the amount of adsorbent per mm. The inventors have, inparticular, found that the amount of adsorbent material in mg, C_(w),per mm in length for a regular format smoking article, and the amount ofabsorbent material in mg, T_(w), per mm in length for a regular formatsmoking article, can be determined in accordance with the range:

10≦(C _(w) +T _(w))≦20,

these values enabling the filter to exhibit appropriate levels of filterpressure drop and hardness, such as those discussed above.

Particular benefits can be achieved if the amount of adsorbent materialand the amount of absorbent material in mg per mm of length for aregular circumference smoking article fall within the range:

11≦(C _(w) +T _(w))≦18,

or more particularly within the range:

12≦(C _(w) +T _(w))≦17.

Advantages can also be achieved using adsorbent and absorbent weights,in mg per mm of length for a regular circumference smoking article, inother ranges, including 10≦(C_(w)+T_(w))≦19, 10≦(C_(w)+T_(w))≦18,10≦(C_(w)+T_(w))≦17, 11≦(C_(w)+T_(w))≦20, 12≦(C_(w)+T_(w))≦20,13≦(C_(w)+T_(w))≦20 and 14≦(C_(w)+T_(w))≦20.

In addition to selected adsorbent and absorbent weights per mm fallingwithin the above ranges, at least one of the adsorbent and absorbentweight C_(w), T_(w) can be greater than a minimum level. For instance,the absorbent level can be equal to or greater than about 1.5 mg per mmin some embodiments of the invention and/or the adsorbent can be equalto or greater than 6 mg per mm, both minimum levels being for a regularcircumference filter, of about 23 mm to 25 mm.

The above ranges can also be applied for use with granular additivesother than adsorbents, such as certain flavourants (where localregulations permit).

The second filter segment 9 can be manufactured using a filtermanufacturing apparatus such as the Turmalin apparatus available fromHauni Maschinenbau AG in Germany.

In cases in which the absorbent weight per mm is less than 3.5 mg per mmand/or the adsorbent weight per mm is less than 9 mg per mm (both for aregular circumference smoking article), and/or the combined adsorbentand absorbent weight per mm is at the lower end of the above ranges, forinstance 12 mg per mm or lower, the inventors have determined that areduction in hardness caused by these low weights can be offset byusing, for instance, a stiffer plug wrap and/or stiffer tipping materialsurrounding the filter. For instance, the plug wrap and/or tipping couldhave a basis weight of greater than 30 g/m², greater than 40 g/m²,greater than 50 g/m², greater than 60 g/m², greater than 70 g/m² orgreater than 80 g/m². Alternatively, multiple layers of plug wrap and/ortipping material can be used.

Known Dalmatian filters, i.e. those comprising carbon particlesdispersed in continuous cellulose acetate tow cut according to therequired segment length, in the regular format, generally have an uppercarbon loading limit of 5 mg/mm in order to keep the pressure drop atlevels desirable for consumers. Higher loading could result in thepressure drop being too high. If it was desired to have a higher loadingthen, in the past, it was usually necessary to use a cavity triplefilter, having mouth-end and tobacco end cellulose acetate tow sectionswith a carbon filled cavity between them. Such cavity filters result inthe removal of a quantity of cellulose acetate for a given filter lengthand so this can have a negative effect, for instance on particularaspects of tar filtration and phenol selectivity. As such, there areclear advantages to being able to increase the loading of additiveswithout causing too great a pressure drop and without the removal offiltration material.

The present inventors accordingly have recognised that by using randomlyoriented discrete short length cellulose acetate fibres for forming thefilter, manufactured using a filter manufacturing apparatus such as theTurmalin apparatus available from Hauni Maschinenbau AG in Germany, andby selecting the amount of adsorbent to be in the range from 6 mg to 16mg per mm on average, and the amount of absorbent to be in the rangefrom 1.5 mg to 8 mg per mm on average (or the other ranges and limitsset out above), for a regular circumference cigarette, improved filterscan be provided whilst maintaining acceptable pressure drop and filterhardness parameters.

FIG. 2 is a schematic illustration of a filter making apparatus, such asthe Turmalin apparatus available from Hauni Maschinenbau AG in Germany,for use in manufacturing filters.

Referring to FIG. 2, a source 21 of cellulose acetate or other filtermaterial is supplied to the filter making apparatus 20, which comprisesa plurality of modules 22-26. A feeder module 22 receives the supply offilter material, for instance crimped continuous fibres such as crimpedcellulose acetate tow, from which it is fed into a cutter and randomiser23. The cutter and randomiser 23 cuts the filter material into shortstaple lengths, for instance 10 mm lengths. Other fibre lengths can beused, as described above in relation to the smoking article 1 describedwith reference to FIG. 1. A filter bander 24 includes a vacuum band ontowhich the cut filter material is provided. This is fed into a rod former25, for forming the band of cut filter material into a rod which iswrapped with a plug wrap. Finally, a segment cutter 26 is used to cutthe rod into filter segments of a desired length.

The filter bander 24 comprises a carding unit which distributes the cutfibres evenly onto the vacuum band, and a plurality of hoppers, two inthe present example, for applying additives, for instance in the form ofgranules or additional fibres. There is also an add-back system whichcan be used if required to feed a third additive into the band of cutfilter material. The add-back system alternatively may be used to feedany loose cut filter material back into the cutter and randomiser 23 toreduce wastage. The filter bander 24 comprises metering rollers whichare adjustable to permit control over the additive loading and to ensureuniformity of the band of cut filter material as it is formed. Thefilter bander 24 also comprises a jet inserter for enabling liquids suchas flavours (where local regulations permit the use of flavours) to beinjected directly into the filter rod.

In use, the Turmalin apparatus operates as follows: the feeder module 22feeds filter material such as crimped cellulose acetate tow into thecutter and randomiser 23. The cutter and randomiser 23 cuts the towfibres into short staple lengths of 10 mm in the present example. Thecut filter material is blown to the carding unit of the filter bander 24from which it is sucked onto the vacuum band, where it is formed into aband of randomly orientated filter material. The bander 24 operates insuch a way that the resultant hand of filter material is mechanicallybonded. Additives are fed into the air stream carrying the filterfibres, and the rod former 25 forms the band into a continuous filterrod, which is bound by a filter plug wrap. The segment cutter 26 cutsthe continuous filter rod, comprising randomly orientated fibres, intosegments of a desired length.

Appreciated advantages of the Turmalin apparatus include: the inclusionof additives, for example carbon, at higher loadings; retention of theactivity of carbon additives because without plasticisers such astriacetin there is no poisoning of the charcoal; and a longer productlife. The filter designs and manufacturing developments created by theinventors which are described below lead to further advantages andimprovements.

It is possible to generate a series of filter capability curves fordiffering tow weights, additive loadings and machinery operating speeds,such that filter designs can be optimised to desired filtercharacteristics, such as pressure drop and hardness level. This therebyincreases the range of different filters which can be manufactured, andwhich may have purposely different capabilities depending on therequirements for a particular product.

FIG. 3 is a graph illustrating the additive weight (in the present casecarbon weight) and tow weight in filters based on preferred ranges fortheir pressure drop and hardness. In particular, the tow weight andcarbon weight required for a filter pressure drop of from 500 to 700mmWg for a 144 mm filter length (3.47 to 4.86 mmWg/mm) and for a filterhardness level from 85% to 95%, according to the Filtrona filterhardness measure, are indicated in the graph, which represents data fromfilters produced using the Hauni Turmalin apparatus. The device can beoperated at speed settings from below 50 m/min up to over 200 m/min. Thecarbon used was 30/70 mesh coconut carbon, dispersed within 8 deniernon-plasticised, crimped randomly oriented cellulose acetate tow fibrescut to 10 mm lengths. For these particular filter parameters, theresulting contour plot of FIG. 3 illustrates the range of tow and carbonweights per mm for a regular circumference smoking article which can beobtained while achieving desired characteristics such as pressure dropand hardness within predefined ranges.

In relation to the pressure drop of the filter, FIG. 4 is a graphillustrating the influence of carbon weight, tow weight and machineryoperating speed on pressure drop for filters. Again, the carbon used was30/70 mesh coconut carbon, dispersed within 8 denier non-plasticised,crimped randomly oriented cellulose acetate tow fibres cut to 10 mmlengths. While the operating speed of the machinery has relativelylittle effect on the pressure drop and the tow weight has a generallylinear relationship, surprisingly the inventors have realised that anincreased carbon weight beyond 10 mg/mm can be shown in some cases toreduce filter pressure drop for a given tow density, based on filtersmanufactured using the Turmalin apparatus. This is a significant result,indicating that the level of carbon can be increased beyond 10 mg/mmwithout having an adverse influence on filter pressure drop.

In relation to the hardness of the filter, FIG. 5 provides three graphsillustrating the influence of carbon weight, tow weight and machineryoperating speed on hardness for filters. Again, the carbon used was30/70 mesh coconut carbon, dispersed within 8 denier non-plasticised,crimped randomly oriented cellulose acetate tow fibres cut to 10 mmlengths. In a similar way to pressure drop, while the operating speed ofthe machinery has relatively little effect on the hardness and the towweight has a generally linear relationship, surprisingly the inventorshave realised that an increased carbon weight beyond 10 mg/mm in factreduces filter hardness for a given tow density for filters manufacturedusing the Turmalin apparatus. This is a significant result, indicatingthat the level of carbon can be increased beyond 10 mg/mm without havingan adverse influence on filter hardness.

Although the additive in the above embodiments has been described asparticles of adsorbent, in particular activated carbon, otheradsorbents, or other additives, can also be used. For instance, theadsorbent could be an ion exchange resin, such as CR20, or othermaterials such as zeolite, silica gel, meerschaum, aluminium oxide(activated or not), carbonaceous resin, magnesium silicate, includingSepiolite (Mg₄Si₆O₁₅(OH)₂.6H₂O) or combinations thereof with or withoutactivated carbon. Also, other additives which modify the smoke drawnthrough the filter, such as flavourant (where local regulations permitthe use of flavourants) for example menthol crystals, or humectantparticles, can be used.

It has previously been known to manufacture filters comprising randomlyoriented discrete tow fibres, for example as described in WO2009/093051. However, similar to conventional acetate tow filters, themanufacturing technique described in WO 2009/093051 can also require theuse of a plasticising agent, e.g. triacetin, to cause bonding within therandomly orientated fibres to give a firm structure. An advantage of theTurmalin apparatus is that it does not require the use of a plasticisingagent. The Turmalin apparatus causes a mechanical bonding within thefibres making the need for plasticiser obsolete. Any undesirable effectscaused by using products such as triacetin are therefore eliminated.

In addition to the above advantage, the present inventors haveappreciated that the Turmalin apparatus, or similar, enables variousfilter designs to be made which offer additional improvements andadvantages. Such improvements and advantages are described in detailbelow.

The inventors have appreciated that the capabilities of the filtersmanufactured using a process such as that of the Turmalin apparatus canbe improved by using materials with smaller particle sizes thantraditionally used. Smaller particles can enhance that filtrationperformance because they have larger surface area.

FIG. 6 is a schematic illustration of a smoking article 31. The smokingarticle 31 comprises a tobacco rod 32 wrapped in a wrapping material 33,in this case cigarette paper, connected longitudinally to a filter 34 bytipping material 35 overlaying the filter 34 and partially overlayingthe wrapping material 33. The filter 34 comprises a first segment 36 atthe mouth-end of the filter 34 comprising crimped cellulose acetate tow37 wrapped in a first plug wrap 38, and a second segment 39 at thetobacco rod end of the filter 34 comprising a first absorbent material40 and a second absorbent material 41 wrapped in a second plug wrap 42.

The first segment 36 is a cellulose acetate segment formed usingcontinuous cellulose acetate fibres and a plasticiser.

The first absorbent material 40 comprises a fibrous filter materialhaving an average fibre denier in the range 7 to 9 and the secondabsorbent material 41, dispersed within the first absorbent material 40,comprises a fibrous filter material having an average fibre denier ofbelow 7, for instance a denier of about from 1 to 6, 2 to 6, 3 to 6, orabout 6, 5, 4 3, 2 or 1. The first and second fibrous filter materials40, 41 comprise short length fibres which are randomly oriented in thefilter.

The second filter segment 39 can be manufactured using the Turmalinapparatus, for instance by supplying a continuous tow of the firstabsorbent material 40 to the feeder 22 and by adding fibres of thesecond absorbent material via one of the additive hoppers in the filterbander 24. Alternatively, supplies of the first and second filtermaterials 40, 41 can each be provided to the feeder 21 of the Turmalinapparatus, such that they are cut and randomised together and processedin a similar way to a single filter material.

The fibres of the first and second materials 40, 41 comprise discreteshort length cellulose acetate fibres (as described herein) in thepresent example, although alternative fibres can also be used. Forinstance, the fibres of the first and/or second material can comprisecellulose acetate, polyvinyl alcohol (PVOH), polylactic acid (PLA),poly(ε-caprolactone)(PCL), poly(1-4 butanediol succinate) (PBS),poly(butylene adipate-co-terephthalate)(PBAT), starch based materials,paper, aliphatic polyester materials and polysaccharide polymers orcombinations therefore.

A further advantage is achievable through the use of nanofibre materialsas a base for catalytic substances to enhance filter performance.Nanofibres have a sufficiently high surface area to volume ratio to havethe potential for catalytic activity. Such nanofibres may be added to afilter using the apparatus of FIG. 2, for instance at the time ofadditive loading through the one or more hoppers in the filter bander 24such that the nanofibres are metered into the airstream within thefilter bander 24.

FIG. 7 is a schematic illustration of a smoking article 51 having afilter including a nanofibre carrying an additive for enhancing orenabling the reduction of at least one component of main stream smokedrawn through the smoking article 51 when in use.

Referring to FIG. 7, the smoking article 51 comprises a tobacco rod 52wrapped in a wrapping material 53, in this case cigarette paper,connected longitudinally to a filter 54 by tipping material 55overlaying the filter 54 and partially overlaying the wrapping material53. The filter 54 comprises a first segment 56 at the mouth-end of thefilter 54 comprising crimped cellulose acetate tow 57 wrapped in a firstplug wrap 58, and a second segment 59 at the tobacco rod end of thefilter 54 comprising nanofibres 60 wrapped in a second plug wrap 61. Thefirst segment 56 is a cellulose acetate segment formed using continuouscellulose acetate fibres and a plasticiser. In the present example thenanofibres 60 are short length randomly oriented fibres mixed withcellulose acetate short length randomly oriented fibres. The nanofibrescomprise carbon nanofibres 60 a supporting zinc oxide (ZnO) particlesacting as a catalytic agent 60 b, for instance enhancing the reductionof HCN in cigarette smoke. In alternative embodiments, other nanofibrematerials and/or other catalytic agents can be used, alone or incombination (including in combination with carbon and/or ZnO), such asGold (Au), for instance for Carbon Monoxide (CO) reduction fromcigarette smoke. The nanofibres 60 can be added as an additive torandomly orientated staple length cellulose acetate fibres using thefilter making apparatus 20 of FIG. 2.

The nanofibres can be of any suitable length for inclusion in a filtersegment, for instance between 1 mm and 15 mm, or from 5 mm to 12 mm. Thediameters of the nanofibres used can be from 25 nm to 900 nm, or from 50nm to 500 nm, or from 100 nm to 300 nm.

In further embodiments of the invention, where local regulations permit,flavour may be provided to filters produced using the Turmalinapparatus.

The addition of flavour to a filter can be achieved using a thread as acarrier. An example of suitable apparatus for inserting threads intofilter material is provided in patent publication no. WO2010/108739 andcorresponding U.S. patent application publication of U.S. applicationSer. No. 13/259,634, the contents of which are incorporated by referenceherein. A Thread insertion device, such as that described inWO2010/108739, can be installed in a central portion of the filtervacuum band with a thread inserting needle carrying the thread into theaxial region of the filter rod as it is formed. Embodiments describedherein involving the insertion of threads into filters are particularlyadvantageous in slim and super slim formats, i.e. below 22 mm diameters,and in particular below 21 mm, 20 mm, 18 mm, 16 mm, 15 mm and 14 mm.

FIG. 8 is a schematic illustration of a smoking article having a filtercomprising randomly oriented discrete short length fibres having athread extending therethrough.

Referring to FIG. 8, the smoking article 151 comprises a tobacco rod 152wrapped in a wrapping material 153, in this case cigarette paper,connected longitudinally to a filter 154 by tipping material 155overlaying the filter 154 and partially overlaying the wrapping material153. The filter 154 comprises a first segment 156 at the mouth-end ofthe filter 154 comprising crimped cellulose acetate tow 157 wrapped in afirst plug wrap 158, and a second segment 159 at the tobacco rod end ofthe filter 154 comprising absorbent material 160. A thread 161 extendsaxially through the second segment 159. The second segment 159 iswrapped in a second plug wrap 162. In the present example the absorbentmaterial 160 comprises randomly oriented discrete short length celluloseacetate fibres.

The inventors have also appreciated that the Turmalin apparatus, orsimilar, may be arranged to permit the inclusion into randomly orienteddiscrete short length fibre filters of capsules, microcapsules or otherencapsulated material, while ensuring uniform distribution of thecapsule contents, such as flavour (where local regulations permit) ordiluents.

In a similar manner as described in relation to carbon loading, it ispossible to add such materials at higher levels in order to deliver moreflavour. Capsules, whether larger capsules such as those with diametersbetween 3 mm and 8 mm, microcapsules or other encapsulated materials,can be pushed into filter tow in an apparatus such as the Turmalinapparatus by directing the capsules through a tube into the filter towat the downstream end of the filter bander. The capsules can, forinstance, be blown into the filter material using high pressure gas, ata frequency corresponding to the speed of the filter bander, such thatcapsules are located in the resulting filter rod at appropriateintervals, and filter segments cut from the filter rod contain thedesired number of capsules. Alternatively, microcapsules could bemetered onto the filter band in a similar way to additives, using one ofthe additive hoppers described above. Embodiments described hereininvolving the insertion of encapsulated flavourants into filters areparticularly advantageous in slim and super slim formats, i.e. below 22mm diameters, and in particular below 21 mm, 20 mm, 18 mm, 16 mm, 15 mmand 14 mm.

FIG. 9 is a schematic illustration of a smoking article 171 having afilter comprising randomly oriented discrete short length fibres havinga capsule disposed therein. Referring to FIG. 9, the smoking article 171comprises a tobacco rod 172 wrapped in a wrapping material 173, in thiscase cigarette paper, connected longitudinally to a filter 174 bytipping material 175 overlaying the filter 174 and partially overlayingthe wrapping material 173. The filter 174 comprises a first segment 176at the mouth-end of the filter 174 comprising crimped cellulose acetatetow 177 wrapped in a first plug wrap 178, and a second segment 179 atthe tobacco rod end of the filter 174 comprising absorbent material 180.An encapsulated flavourant 181, in the present case in the form of acapsule, is disposed within second segment 179. The second segment 179is wrapped in a second plug wrap 182. In the present example theabsorbent material 180 comprises randomly oriented discrete short lengthcellulose acetate fibres.

FIG. 10 is a schematic illustration of a smoking article having a filtercomprising randomly oriented discrete short length fibres havingmicrocapsules disposed therein.

Referring to FIG. 10, the smoking article 191 comprises a tobacco rod192 wrapped in a wrapping material 193, in this case cigarette paper,connected longitudinally to a filter 194 by tipping material 195overlaying the filter 194 and partially overlaying the wrapping material193. The filter 194 comprises a first segment 196 at the mouth-end ofthe filter 194 comprising crimped cellulose acetate tow 197 wrapped in afirst plug wrap 198, and a second segment 199 at the tobacco rod end ofthe filter 194 comprising absorbent material 200. Encapsulatedflavourant 201, in the present case in the form of a plurality ofmicrocapsules, is disposed within second segment 199. The second segment199 is wrapped in a second plug wrap 202. In the present example theabsorbent material 200 comprises randomly oriented discrete short lengthcellulose acetate fibres.

In addition to encapsulated flavourants, other forms of flavour additive(where local regulations permit the use of such additives) can be addedto a filter comprising randomly oriented discrete short length fibres.For instance, flavour additives could be added in botanical form, suchas mint or tobacco leaves or other plant leaves, plant seeds, plant peeletc. Such additives can be added to the additive hoppers in the bandformer of the Turmalin apparatus and therefore metered into the filtermaterial air stream as the filter band is formed, for instance usingdiscrete short length cellulose acetate fibres as described herein.Since no plasticiser is used in the randomly oriented discrete shortlength fibre filter, flavour release from botanical additives can beenhanced.

It is envisaged by the inventors that additional materials notpreviously used in filter manufacturing may be used in manufacture usinga Turmalin apparatus or similar.

In one embodiment, shredded sheet materials, including new sheetmaterials, are included within the filter material. Such sheet materialsinclude sheet materials formed from botanicals, such as mint and ormenthol, tobacco or reconstituted tobacco. A person skilled in the artwill appreciate that the list provided is not limiting and that anysuitable sheet material may be used. The benefits of using such sheetmaterials in shredded form are that they can improve the dispersibilityof the material within the filter and also improve the degradability ofthe filter material. Furthermore, the use of new materials may be usedto improve the performance of the filter and/or modify characteristicsof smoke drawn through the filter.

FIG. 11 is a schematic illustration of a smoking article having a filtercomprising randomly oriented discrete short length fibres havingshredded sheet material disposed therein.

Referring to FIG. 11, the smoking article 211 comprises a tobacco rod212 wrapped in a wrapping material 213, in this case cigarette paper,connected longitudinally to a filter 214 by tipping material 215overlaying the filter 214 and partially overlaying the wrapping material213. The filter 214 comprises a first segment 216 at the mouth-end ofthe filter 214 comprising crimped cellulose acetate tow 217 wrapped in afirst plug wrap 218, and a second segment 219 at the tobacco rod end ofthe filter 214 comprising absorbent material 220 in which shredded sheetmaterial 221 is dispersed. The second segment 219 is wrapped in a secondplug wrap 222. In the present example the absorbent material 200comprises randomly oriented discrete short length cellulose acetatefibres and the shredded sheet material 221 comprises shreddedreconstituted tobacco sheet.

The shredded sheet material 221 can comprise a material formed fromfibres of cellulose acetate, polyvinyl alcohol (PVOH), polylactic acid(PLA), poly(ε-caprolactone)(PCL), poly(1-4 butanediol succinate) (PBS),poly(butylene adipate-co-terephthalate)(PBAT), starch based materials,paper, aliphatic polyester materials or polysaccharide polymers and/orcombinations therefore.

The inventors have also appreciated the potential for combiningdegradable or otherwise alternative fibres such as PVOH fibres withconventional cellulose acetate fibres. PVOH is typically not used inconventional filter manufacture because PVOH cannot usually be crimped.The inclusion of PVOH or other non-crimped fibres with another material,i.e. cellulose acetate, mean that this problem can be overcome. Usingsuch materials can result in a filter with improved degradability andwater solubility. Other materials include poly(ε-caprolactone)(PCL),poly(1-4 butane diol succinate)(PBS), poly(butyleneadipate-co-terephthalate)(PBAT), starch based materials, paper,aliphatic polyester materials and polysaccharide polymers.

Also, other crimped materials such as PLA can be combined withconventional cellulose acetate fibres.

In one embodiment, in order to add PVOH or other non-crimped fibres to afilter, or PLA or other crimped fibres to a filter, the Turmalin feeder22 is arranged to feed two ropes of raw filter material into the cutterand randomiser 23. As such, the number of processing steps is reduced bynot first turning the material into sheet material, and instead pullingthe material straight in as tow.

In addition, the number processing steps may be further reduced if thestep for turning material into tow material is omitted. In suchembodiments, there is further no requirement to feed, cut and randomisethe fibres. Rather, the PVOH, PLA or other material in raw fibrous formcan be mixed directly with a bag of short staple cellulose acetatefibres lanced straight into the Turmalin apparatus.

In another embodiment, PVOH fibres (or other non-crimped fibres) or PLAfibres (or other crimped fibres) can be metered into the filter tow inthe filter bander 24 using one of the additive hoppers described above.

FIG. 12 is a schematic illustration of a smoking article having a filtercomprising randomly oriented discrete short length fibres havingdegradable fibres disposed therein. Referring to FIG. 12, the smokingarticle 231 comprises a tobacco rod 232 wrapped in a wrapping material233, in this case cigarette paper, connected longitudinally to a filter234 by tipping material 235 overlaying the filter 234 and partiallyoverlaying the wrapping material 233. The filter 234 comprises a firstsegment 236 at the mouth-end of the filter 234 comprising crimpedcellulose acetate tow 237 wrapped in a first plug wrap 238, and a secondsegment 239 at the tobacco rod end of the filter 234 comprisingabsorbent material 240 in which PVOH fibres 241 are dispersed. Thesecond segment 239 is wrapped in a second plug wrap 242. In the presentexample the absorbent material 240 comprises randomly oriented discreteshort length cellulose acetate fibres.

Conventional filter manufacturing techniques manufacture filter rodswith a uniform density in a longitudinal direction. The inventors haveappreciated that it is possible to purposely provide variable densityalong the length of the filter rod. In one embodiment the density may becaused to vary such that when the filter rod is cut into individualsegments, the filter segment comprises dense ends, and a centre portionof lower density. This is advantageous as it does not rely on the towcrimp to hold fibres in the filter.

FIG. 13a is a schematic illustration of a filter rod 245 comprisingalternately arranged longitudinal regions 246 of higher average densityand regions 247 of lower average density. The filter rod 245 can be usedto produce multiple filter segments, each comprising a homogeneous unitof filter material, for instance varying only in density along itslength, for use in smoking article filters. For instance, the filter rod245 can be cut at the centre 248 of each of the regions 246 of higheraverage density such that the resulting filter segments have ‘denseends’. Line graph 249 illustrates the density of filter material alongthe length of the filter rod 245, in the present example varying in anundulating or sinusoidal manner. In alternative examples, the density offilter material along the length of the filter rod 245 can vary in otherways, for instance in a sequence of 1, 2, 3, 4 or more steppedvariations in the density for each density cycle along the length of thefilter rod 245. The filter material illustrated in FIG. 13a comprisesdiscrete short length cellulose acetate fibres, but can alternatively beanother fibrous filter material described herein, such as polyvinylalcohol (PVOH), polylactic acid (PLA), poly(ε-caprolactone)(PCL),poly(l-4 butanediol succinate) (PBS), poly(butyleneadipate-co-terephthalate)(PBAT), starch based materials, paper,aliphatic polyester materials and polysaccharide polymers orcombinations therefore. The material can also contain additives, such asadsorbents as herein described.

The denser portions, as shown in FIG. 13a , are such that the fibres,even if some or all of the fibres are not crimped, are prevented fromspilling out of filter segments, once cut. The embodiment of FIG. 13aaccordingly can enable the use of materials which are not suitable forcrimping, for example PVOH and non-woven materials. This, in turn, canlead to increased degradability and water solubility as described above.The filter material can therefore be formed from a single fibrousmaterial, or multiple combined materials such as cellulose acetatefibres combined with those of another material.

A person skilled in the art will appreciate different ways in which thedensity of the filter rod 245 may be caused to vary along its length.For example, this could be achieved by using machinery having a variablespeed garniture or pulsing higher volumes of filter material, oradditives, when forming filter material onto a suction band.Alternatively or in addition, the filter suction band can be adapted toenable regions of higher average density and regions of lower averagedensity to be formed on the band, for instance by varying the airresistance of the band in different regions such as by varying the sizeand/or frequency of apertures on the band according to the desireddensity pattern. The timing of the production line can be controlledsuch that the segment lengths are controlled and cut accordingly.

FIG. 13b is a schematic illustration of a section of a filter formingsuction band, such as that used in the filter bander 24 of the Turmalinapparatus, for producing filter segments having regions of higheraverage density and regions of lower average density. Referring to FIG.13b , the filter forming suction band 250 comprises a nylon mesh 251formed so as to have first regions 252 having larger mesh apertures anda lower density of mesh material and second regions 253 having smallermesh apertures and a higher density of mesh material. The first regions252 accordingly have a lower resistance to air than the second regions253. In use, the fibres in the filter bander air stream will be drawntowards the first regions 252 having larger mesh apertures with greaterforce than towards the second regions 253 having smaller mesh apertures.As a result, a greater average density of filter fibres will bedeposited in the first regions 252 than in the second regions 253. Theresulting filter will therefore have regions of greater average densitycorresponding to the first regions 252 of the suction band 250 andregions of lower average density corresponding to the second regions 253of the suction band 250.

In the example of FIG. 13b , the size and number of apertures is variedalong the length of the suction band 250 in an undulating manner.However, in other embodiments, only the size of the apertures can bevaried along the length of the suction band, for instance by using asolid band with varying aperture sizes cut into the band at differentlongitudinally spaced repeating intervals. Alternatively, in otherembodiments, only the number of apertures is varied along the length ofthe suction band, for instance by using a solid band with varyingnumbers of apertures for a given area of band cut into the band atdifferent longitudinally spaced repeating intervals along the band.Also, rather than following an undulating variation in air resistancealong the length of the suction band, the apertures can be arranged suchthat 1, 2, 3, 4 or more step changes in the density of filter materialoccur in repeating intervals along the length of the band.

The inventors have also realised that it is possible to create filtershaving a non-conventional cross-sections. In conventional filter rods,if a non-circular shape was desired it would require a substantialquantity of plasticiser and steam to form the required shape. Inpractice this has not been readily achievable. However, the inventorshave appreciated that the way in which the Turmalin apparatus creates anoblong band which has a mechanical strength can be adapted for othercross-sectional shapes of the filter material. For instance, theTurmalin apparatus could be adapted to create a band other than anoblong or the filter material can be forced into a desired shape, forinstance via a shaped aperture or using an appropriately shapedgarniture belt. For example, the band of filter material may be formedon the belt of the filter bander 24 or passed through an appropriatelyshaped aperture or garniture belt, such that the filter has a polygonal,for instance triangular, square, rectangular, pentagonal or hexagonalcross-section, or another non-circular cross-section, such as an oval orelliptical cross-section, and the structural stability of the band ofmaterial can be such that the band maintains the desired shape. Anotherembodiment may make use of appropriately designed wrapping and steamingprocesses. The resulting filter may have a cross section with acircumference smaller than 16 mm or a circumference greater than 25 mm.

FIG. 14 is a schematic illustration of a smoking article 291 having afilter comprising an elliptical cross-section.

Referring to FIG. 14, the smoking article 291 comprises an ellipticallycross-sectioned tobacco rod 292 wrapped in a wrapping material 293, inthis case cigarette paper, connected longitudinally to a filter 294 bytipping material 295 overlaying the filter 294 and partially overlayingthe wrapping material 293. The filter 294 comprises a single filtersegment 296 at the mouth-end of the smoking article 291 comprisingabsorbent material 297 wrapped in a first plug wrap 2980. The segment296 has an elliptical cross-section. In the present example theabsorbent material 297 comprises randomly oriented discrete short lengthcellulose acetate fibres. An additional plastic mesh, a fabric, or otherpermeable barrier (not shown) can be applied across the mouth-end of thefilter 294 to prevent individual filter fibres from coming away from thefilter 294.

FIG. 15 is a schematic illustration of a smoking article 311 having afilter comprising a square cross-section.

Referring to FIG. 15, the smoking article 311 comprises a squarecross-sectioned tobacco rod 312 wrapped in a wrapping material 313, inthis case cigarette paper, connected longitudinally to a filter 314 bytipping material 315 overlaying the filter 314 and partially overlayingthe wrapping material 313. The filter 314 comprises a single segment 316at the mouth-end of the smoking article 311 comprising absorbentmaterial 317 wrapped in a plug wrap 318. The segment 316 has a squarecross-section. In the present example the absorbent material 317, 320comprises randomly oriented discrete short length cellulose acetatefibres. An additional plastic mesh, a fabric, or other permeable barrier(not shown) can be applied across the mouth-end of the filter 314 toprevent individual filter fibres from coming away from the filter 314.

The filters 294, 314 of the embodiments illustrated in FIGS. 14 and 15can also include other features, such as additives dispersed within thefilter fibres and/or ventilation applied to the filters, for instance aslaser formed holes.

The inventors have also realised that it is possible to produce filtersincluding randomly orientated short-length fibres formed into a cylinderhaving a circumference smaller than 16 mm, 15 mm, 14 mm or 13 mm, or acircumference greater than 25 mm, 26 mm, 27 mm or 28 mm. A single denierfibre can be used, for instance having a denier from about 7 to about 9,and the amount used in the filter per mm varied according to the filtercircumference required. For instance, the amount of randomly orientatedshort-length fibres per mm can be reduced for super slim format filtersand increased for regular format filters. This differs from knowncontinuous tow filter manufacture where different fibre deniers areusually required for different circumference filters.

In the foregoing examples, the second filter segments 9, 39, 59, 159,179, 199, 219 and 239 (shown in FIGS. 1 and 6 to 12) containing randomlyoriented discrete length fibres have been described as tobacco-endcomponents of dual filters, with known cellulose acetate first filtersegments at the mouth-end. However, other arrangements are possible. Forinstance, the second segments can be adapted for use at the mouth end ofcigarette filters. This can be achieved by preventing individual fibresfrom coming away from the filter segment during use, for instance byincluding a plasticiser (for instance a localised plasticiser in aportion at the mouth end of the mouth-end segment) to hold the randomlyoriented discrete length fibres and/or any additives dispersed thereinin place, or by using a plastic mesh, a fabric, or other permeablebarrier preventing individual fibres from reaching the mouth of aconsumer. The second filter segments can also be used as the central ortobacco-end filter segment of a three-part filter, or any segment of afour, five or six-part filter, as required. The first filter segmentscan also be other than conventional cellulose acetate segments wrappedin plug wrap. For instance, non-wrapped acetate (NWA) sections can beused as the first filter segments described herein.

Also, the first and second filter segments of the embodimentsillustrated in FIGS. 1 and 6 to 12 have been shown to have individualplug wraps and be held together and connected to the tobacco rod using atipping material. However, alternatively, a further outer plug wrap (notshown) can be wrapped around the first and second filter segments andused to connect the first and second filter segments to each other, andthe combined filter unit can then be connected to the tobacco rod usinga tipping material.

Although the randomly oriented fibres described herein have beendescribed as being crimped, non-crimped fibres can also be used, aloneor mixed with crimped fibres. Also, the randomly oriented fibres havebeen described as being of 10 mm fibre lengths (when extended), orlengths in the range from 5 mm to 25 mm, or from 6 mm to 20 mm, 7 mm to20 mm or 7 mm to 15 mm. The second segments can also include averagefibre lengths outside this range, and/or mixtures of groups fibres ofdifferent average lengths, depending on the requirement of the filterconcerned and the fibrous materials available.

Filter arrangements described herein can be modified to include one ormore transparent sections in the plug wrap and/or tipping paper so as toallow the internal filter parts to be seen by smoking article consumers.For instance, the second plug wrap used to wrap the second filtersegment may comprise a transparent material such as Natureflex™ filmavailable from Innovia Films in the United Kingdom. The tipping couldcomprise one or more window cut-outs, or sections of transparentmaterial such as Natureflex™ film, to enable the internal filter partsto be seen through the tipping and plug wrap. Alternatively, the tippingcould be applied in two bands with a gap between them revealing thetransparent plug wrap beneath, or the tipping could be made entirely ofa material such as Natureflex™ film. Some embodiments may includetransparent ‘window’ section filters such as those described in patentpublication no. WO2009/106374, the contents of which (including anycorresponding US publications) are incorporated by reference in theirentirety herein.

In order to address various issues and advance the art, the entirety ofthis disclosure shows by way of illustration various embodiments inwhich the claimed invention(s) may be practiced and provide for superiorsmoking article filters. The advantages and features of the disclosureare of a representative sample of embodiments only, and are notexhaustive and/or exclusive. They are presented only to assist inunderstanding and teach the claimed features. It is to be understoodthat advantages, embodiments, examples, functions, features, structures,and/or other aspects of the disclosure are not to be consideredlimitations on the disclosure as defined by the claims or limitations onequivalents to the claims, and that other embodiments may be utilisedand modifications may be made without departing from the scope and/orspirit of the disclosure. Various embodiments may suitably comprise,consist of, or consist essentially of, various combinations of thedisclosed elements, components, features, parts, steps, means, etc. Inaddition, the disclosure includes other inventions not presentlyclaimed, but which may be claimed in future.

1-15. (canceled)
 16. A smoking article filter, comprising randomlyoriented short length fibers of a first material and randomly orientedshort length fibers of a second material, wherein the second materialcomprises at least one material including at least one of polyvinylalcohol (PVOH), polylactic acid (PLA), poly(ε-caprolactone)(PCL),poly(1-4 butanediol succinate)(PBS), poly(butyleneadipate-co-terephthalate)(PBAT), starch based materials, paper,aliphatic polyester materials and polysaccharide polymers, nanofibers,carbon nanofibers and/or nanofibers supporting a catalytic agent. 17.The filter according to claim 16, wherein the first material comprisescellulose acetate.
 18. The filter according to claim 16, wherein thesecond material comprises a non-crimped material.
 19. The filteraccording to claim 16, wherein the catalytic agent comprises zinc oxide(ZnO) or gold (Au).
 20. The filter according to claim 16, wherein thenanofibers have a length between 1 mm and 15 mm.
 21. The filteraccording to claim 16, wherein the filter has a non-cylindrical shape.22. The filter according to claim 16, wherein the filter has acylindrical shape and a circumference less than 16 mm or greater than 25mm.
 23. The filter according to claim 16, further comprising a flavorrelease component.
 24. The filter according to claim 17, wherein thesecond material comprises a non-crimped material.
 25. A smoking articlecomprising a filter according to claim 16.